This invention relates to a rear suspension apparatus for use in a motor vehicle, and more particularly, to an independent rear suspension apparatus.
With a recent tendency to equip motor vehicles with high-output engines, high-performance tires have come to be used for vehicles, and also there are various requirements for suspension apparatuses connecting tires, i.e., wheels, to a vehicle body, to improve the drivability and running stability of the vehicles so that driving the vehicle is comfortable. One of these requirements is to ensure sufficient freedom of design in setting the characteristics of changes of the wheel alignment including the toe angle change characteristic and the camber angle change characteristic of the wheels, etc. An example of a suspension apparatus meeting this requirement is a so-called multilink suspension apparatus, which is disclosed, e.g., in U.S. Pat. No. 4,444,415 (patent family members: British Patent No. 2091175; German Patent No. 3048794). According to this patent, a rear suspension apparatus 10 comprises, as shown in FIGS. 10 and 11, a wheel carrier 11 rotatably supporting a rear wheel 2, an upper arm assembly 14 connecting the wheel carrier 11 and a vehicle body and including an upper front arm 12 and an upper rear arm 13, a lower arm assembly 17 connecting the wheel carrier 11 and the vehicle body and including a lower front arm 15 and a lower rear arm 16, and a toe control arm 18 for regulating the toe angle of the rear wheel 2.
In this rear suspension apparatus 10, a desired toe angle and a desired camber angle can be obtained by suitably setting the individual lengths and relative vertical mounting positions of the arms 12, 13, 15, 16 and 18 of the arm assemblies 14 and 17, as well as the orientation of these arms, i.e., the mounting angles with respect to the axis of the vehicle body. Further, when the suspension apparatus 10 moves vertically together with the rear wheel 2, the arms 12, 13, 15, 16 and 18 are swung while interfering with each other, whereby the toe angle and the camber angle are respectively changed.
However, the prior art suspension apparatus 10 requires five arms 12, 13, 15, 16 and 18 arranged between the wheel carrier 11 and the vehicle body, and thus is complicated in structure and allows for little space between the arms, making the mounting of the arms very difficult. To permit an easy mounting of the arms, sufficient space may be provided between the arms, but this results in an undesirable increase in the overall size of the suspension apparatus 10. An increased size of the suspension apparatus 10 not only imposes restrictions on the dimensions of the passenger's compartment, trunk room, fuel tank, etc. of the vehicle but also narrows the freedom of arrangement of the exhaust pipe extending from the engine, and the fuel pipe connecting the fuel tank and the engine, and hence the manufacturing cost of vehicles increases.
Moreover, the toe angle change characteristic and the camber angle change characteristic of the rear suspension apparatus 10 are determined by the so-called link interference occurring when the arms 12, 13, 15, 16 and 18 swing as mentioned above, and accordingly are in an interdependent relationship. Thus, it is not possible to suitably set these change characteristics independent of each other.